Silicone oils were first used in dryer sheet fabric conditioners as an ironing aid as described in Rudy et al. in U.S. Pat. No. 4,421,711. The inclusion of polydiorganosiloxanes in tumble dryer sheet applications have been shown to improve the anti-static performance of the fabric conditioners as described in Karsprzak et al. in U.S. Pat. No. 4,767,548. Karsprzak discloses the use of polydimethylsiloxanes, polyphenylmethylsiloxanes and dimethylsiloxane-glycol copolymers in its dryer sheet formulations.
Additionally, organo-modified silicones useful as coactives in tumble dryer sheets are disclosed in U.S. Ser. No. 07/532,488 (disclosing alkyl silicones and alkylamino silicones) and U.S. Ser. No. 07/532,473 (disclosing salt complexes of amino silicones combined with Bronsted acids, in particular fatty acids). The use of conventional silicone oils are described in both pending U.S. applications as optional ingredients which may be added to the dryer sheet formulations.
Silicones have been used extensively in aqueous dispersions or rinse-cycle fabric softening compositions as described in Dumbrell et al. in GB 1,549,180; Burmeister et al. in U.S. Pat. No. 4,818,242; Konig et al. in U.S. Pat. No. 4,724,089; Konig et al. in U.S. Pat. No. 4,806,255; Dekker et al. in U.S. Pat. No. 4,661,267 and Trinh et al. in U.S. Pat. No. 4,661,269. A fabric softening composition containing emulsified silicone in combination with conventional cationic softening agents is also taught in Barrat et al. in U.S. Pat. No. 4,446,033. The aqueous compositions are used during the aqueous rinse cycle of a laundry process. Conditioning agents such as ion-pair wax composites have been used in detergent compositions by Caswell et al. in U.S. Pat. No. 4,913,828.
Unfortunately, it has been observed that the addition of either conventional silicone oils or certain organo-modified silicones in formulations used for coating dryer sheets, in the absence of a solvent, causes physical separation of the components of the compositions leading to uneven coating of sheet substrates.
Surprisingly, it has been found that specific organo-modified silicones function as emulsifiers for particular silicone oils in hydrocarbon based fabric conditioning formulations to form a stable fabric conditioning composition. The present invention eliminates the problem of physical separation of the composition's components leading to uneven coating of tumble dryer sheets. Furthermore, high levels of H.sub.2 O or solvents are avoided in the invention which often lead to progressing difficulties and undesirable product attributes, such as tackiness or uneven coating of the sheets.
It is therefore an object of the present invention to provide an emulsified silicone mixture in combination with a fabric conditioning active to provide stable fabric conditioning compositions.
A further object of the present invention is to provide such emulsified silicone mixture/fabric conditioning compositions which provide improved softening and anti-static benefits when applied to fabrics in a tumble dryer.
A further object of the present invention is to provide a fabric conditioning composition which is stable when used in detergent formulations, even in those formulations containing harsh surfactants such as the alkyl sulfates.